A disk brake apparatus includes a disk rotor to be fixed to an axle, a disk brake friction pad assembly constituted of a torque receiving plate disposed opposed to the disk rotor and lining members assembled to the disk rotor side surface of the torque receiving plate, and a brake caliper to be fixed to a vehicle body frame and including therein an actuator for advancing and retreating the torque receiving plate with respect to the disk rotor, whereby a braking force is generated by sliding friction caused when the torque receiving plate is advanced toward the disk rotor to thereby press the lining members against the disk rotor.
In a disk brake apparatus for a railway vehicle, since a disk rotor and a friction pad assembly are large in size, when lining members to be pressed against the disk rotor are formed of integral parts, such area of the lining members as is not contacted with the disk rotor is increased due to the undulation of the disk rotor caused by frictional heat or the like, whereby stable frictional area cannot be maintained and thus stable braking characteristics cannot be secured.
In solving such problems, there is provided a friction pad assembly in which multiple second link plates are arranged substantially in a plane on the torque receiving plate, a large number of first link plates are independently swingably on the second link plates, and a large number of lining assemblies are arranged independently swingably on the first link plates, whereby as the torque receiving plate moves toward the disk rotor, the lining assemblies on the first link plates are contacted with the disk rotor (see the patent document 1).
In the thus-structured friction pad assembly, the finely divided lining assemblies are contacted with the disk rotor surface through their individual swinging operations following the undulated surface of the disk rotor, thereby being able to maintain a stable friction area and thus stable braking performance.
There is also proposed a disk brake friction pad assembly with the above friction pad assemblies improved which includes a rotation preventive device for preventing the rotation of the lining assemblies when they are pressed against the disk rotor, thereby preventing the occurrence of braking torque transmission loss and brake noises (see the patent document 2).